The present invention relates to a system for plumbing the water supply connections to dialysis machines in a dialysis treatment unit. A system for fluid delivery in a dialysis clinic is discussed in U.S. patent application Ser. No. 09/065,780 filed Apr. 23, 1998, entitled "System for Fluid Delivery in a Dialysis Clinic," which is hereby incorporated herein by reference.
In renal failure, the filtrate formation decreases or stops completely. Nitrogenous waste accumulate quickly in the blood when the tubule cells are not working, a condition called azotemia, and blood pH tumbles to the acidic range. To prevent consequences of azotemia, the blood must be cleansed of metabolic waste and its ionic composition must be adjusted to normal levels by dialysis while the kidneys are shut down. In hemodialysis, which uses an "artificial kidney" apparatus, the patient's blood is passed through a membrane tubing that is permeable only to selected substances, and the tubing is immersed in a bathing solution that differs slightly from normal cleansed plasma.
FIG. 1 shows a prior art renal dialysis apparatus for performing renal dialysis. The apparatus depicted in FIG. 1 includes a cellophane membrane 12 (tubing containing blood). The cellophane or polysulfone membrane 12 is immersed in dialyzing (bathing) solution 14. The patient's blood passes through an arterial bloodline 16 and is pumped through the cellophane membrane 12 with the aid of a blood pump 18. Blood passes through the cellophane membrane 12 through a venous bloodline 20 back to the patient. A bubble trap 22 is positioned between the cellophane membrane 12 and the venous bloodline 20.
Compressed air 24 forces fresh dialyzing solution 26 through the cellophane membrane 12. The fresh dialyzing solution 26 is passed through a constant temperature vat 28 so that it will not adversely effect the temperature of the patient's blood. As fresh dialyzing solution passes into the dialysizer 14 (also referred to as bathing solution 14) used dialyzing solution 30 is passed out.
It is known by those with skill in the art that dialysis treatment is pressure sensitive. To operate properly dialysis machines must generally operate within known parameters. One of the parameters is the pressure of the fresh dialyzing solution 26 applied to the dialysizer 14. The following prior art discusses methods and apparatus for the parameters of dialysis machines: (1) U.S. Pat. No. 5,276,611 by Ghiraldi entitled "Management Of Parameters Relating To A Dialysis Treatment"; (2) U.S. Pat. No. 4,747,822 entitled "Continuous Flow Peritoneal Dialysis System And Method"; (3) U.S. Pat. No. 5,643,201 entitled "Continuous Peritoneal Dialysis Apparatus" by Peabody, et al.; and (4) U.S. Pat. No. 5,792,367 entitled "System And Method For Monitoring A Flow Of Dialysis Fluid In A Dialysis Machine" by Mattisson, et al, whereby these patents are hereby incorporated herein by reference.
To avoid bacterial growth, and satisfy government requirements, it is required that the flow rate through dialysis solution supply piping be no less than three feet per second. FIG. 2 shows a prior art dialysis plumbing system 32 for supplying water or dialysate 34 to a plurality of dialysis machines 36.
In the prior art dialysis plumbing system 32 shown in FIG. 2, the source of dialysate 34 is pumped by a pump 38 through a supply line 40 to the plurality of dialysis machines 36. A return line 42 is connected to the supply line 40. A flow meter 44 is located proximate the dialysate source 34 to monitor the flow rate in the return line 42. If the flow rate measured at the flow meter proximate the source on the return line is not less than three feet per second, then the flow rate through the entire piping will be no less than three feet per second.
In a typical hospital environment, the source 34 may be located hundreds of feet from the actual clinic containing the dialysis machines 36. The clinic itself may be hundreds of feet long. It will be appreciated that the supply line 40 may be many of hundreds of feet long. Thus, in order to maintain a flow rate of three feet per second at the return end 46 of the return conduit (return line) 42, very high pressures may be necessary at the early portion of the supply conduit (supply line) 40 just downstream of the pump 38 (i. e., the front end of the system). This causes considerable difficulties in designing plumbing systems for dialysis clinics. To achieve a 3 fps flow rate at the back end (return end) of the piping layout, prior art techniques require significant pressures at the front end of the system. Thus, the front end of the piping layout drives the pump and piping material and joining strength requirements. This leads to using overpowered and expensive pumps, and overbuilt piping. Operational costs of such over-pressured systems are simultaneously inflated. There have been instances of piping failures of such systems, and instances of damage to equipment. Additionally, pressure reducing devices are often required such that the dialysis machines connected to the early portion of the fluid system are not over-pressured. It is believed that the present invention overcomes these problems.